The results shown in this paper are the out-of-plane displacement signals versus time (where zero time corresponds to the start of the operation of the source) obtained on the top surface of the steel cylinder at a propagation distance of 100 mm (radial direction) from the capillary fracture. The code uses a uniform cell size (or element size) in both the axial and radial directions.
The longer rise-time (than expected from the glass capillary fracture) allowed modeling of the whole block for a longer time period with reasonable computer resources.
Since the actual temporal shape and the rise time of the source generated by the glass capillary fracture are not known, different shapes and rise times were evaluated.
Thus, it appears that the release of the normal stresses from the glass capillary fracture is not a step in time.